Plunger bar

ABSTRACT

A plunger apparatus is presently disclosed that includes a housing, and a probe slidably supported by the housing. A damping assembly is supported by the housing and cooperating with the probe. The housing, preferably, has a proximal portion and a distal portion wherein the probe is slidably mounted within the housing and extending axially from the distal portion. The probe, desirably, has an increased diameter portion at a proximal end thereof and a penetrating tip adjacent a distal end thereof. A hammer mechanism is provided that is slidably supported by the housing and cooperatively engaging the probe and cooperating with the damping assembly. The housing may also include a handle assembly. A method for using the plunger apparatus is also disclosed.

This application claims the benefit of U.S. Provisional No. 60/062,232filed Oct. 16, 1997.

BACKGROUND

1. Technical Field

The present disclosure relates generally to an apparatus and method fora manually operated plunger bar for creating holes. In particular, theplunger bar is designed to attenuate transmitted shock forces betweenthe tool and the operator.

2. Description of Related Art

Plunger bars are used to create holes in soil, concrete, etc. The mostcommon users are gas utility personnel which use the devices to makeholes in the ground or between cracks in pavement in order to insert agas detection sniffer and locate possible gas leaks. The prior artplunger bar is a manually operated device, designed to be portable andstowable on a service truck for use at remote locations.

FIG. 1 shows an assembly of the prior art plunger bar 10. The plungerbar is generally used in a substantially vertical orientation. Theplunger bar comprises a handle 26 which has a piston 18 and a barrel 16.The barrel 16 is free to slide down the length of the piston 18 and thebarrel's motion is halted upon impact with a flange 20 located at thelower end of the piston 18. The barrel 16 envelopes the piston 18 whenthe barrel is in the down position. The barrel has a hammer 14 attachedat its lower end which is consequently also the point of impact with theflange 20 when the plunger bar 10 is in use. The hammer supplies extraweight to the barrel 16 hence increasing the impact load when impactingthe flange 20. On the end of piston 18 opposite the barrel 16, there isa probe 30 which comprises a solid rod 22 fixedly attached to the piston18 and a removable conical tip 28 at the free end. The tip 28 cantherefore be replaced if damaged. The removable tip 28 is generallysized 3/16 inches to 1/4 inches larger than the diameter of the rod 22.This is to reduce the friction on the rod when a portion of the rod isburied during use.

The barrel 16 is raised by an operator to a maximum height as defined bythe hammer 14 and a flange 12 on the end of the piston 18 opposite theprobe 30. At this point the operator accelerates the barrel 16 byreleasing it or driving it downward. The downward velocity of the barrel16 and hammer 14 increases until impact. The combined mass of the barrel16 and hammer 14 multiplied by the velocity at impact gives the momentumimparted to the flange 20 thereby forcing the probe 30 with theremovable conical tip 28 into the ground. The penetration of the rodinto the ground is achieved when the impulsive impact force of thebarrel 16 and hammer 14 overcome the soil resistance force. After theimpact, the hammer 14 and barrel 16 recoils and loses contact withflange 20, and the probe 30 is driven further into the ground.

An operator is responsible for securing the plunger bar 10 uprightduring its operation. The operator also provides the necessary energy tothe barrel 16 by lifting it and forcing it downward. In order to be ableto complete both activities, it is necessary for the operator to holdthe barrel 16 through the impact. This presents some difficulty whenharder soils, rocks, concrete, etc. are encountered. Softer soils dampout harmful vibrations, but when a very high resistance is encounteredthe vibrations due to impacts are no longer damped and are transferredthrough the plunger bar 10 into the operator. In very high resistancemedia, the probe 30 cannot penetrate, and this reduces the impact timeto a minimum forcing the operator to experience the maximum impactforce.

The impact forces transferred to the operator can cause injury.Immediate damage is possible due to stresses imparted to the arms andwrists of the operator. Also fatigue injuries are common over time orwith repetitive use of the plunger bar 10. Therefore, a need exists fora plunger bar that reduces stresses imparted to operators by reducingthe impact loads during operation.

SUMMARY

An object of the present disclosure is to provide a plunger bar whichreduces fatigue and stress to an operator resulting from an impactforce, and also increases the penetration force of the probe.

The present apparatus comprises a plunger bar including a probe which isdriven into the ground by manually forcing it downward, whereby thedriving effect is supplemented by the provision of a hammer enclosedwithin a slidably moving barrel within the plunger bar housing. Impactswhich are potentially harmful to the human operators, created by shockwaves that cause stress in the operator's arms and wrists, areattenuated in the plunger bar through the use of a spring-damperarrangement located within the housing. Thus, a plunger bar is disclosedwhich reduces the hazards to the human operator. Furthermore, thespring-damper arrangement advantageously enhances the penetration forceof the probe.

A plunger apparatus is disclosed that includes a housing, a probeslidably supported by the housing, a hammer mechanism slidably supportedby the housing and cooperatively engaging the probe to distally advancethe probe into the surface, and a damping assembly supported by thehousing that includes at least one energy absorbing member andcooperates with the hammer mechanism to attenuate impact forcesgenerated during operation of the apparatus. Desirably, the dampingassembly is positioned to generate a recoil force for cooperating withthe hammer mechanism to increase impact forces for driving the probeinto a surface. Most desirably, the at least one energy absorbing memberincludes a spring assembly. Preferably, the probe has an increaseddiameter portion to retain the probe within the housing.

In a preferred embodiment, the hammer mechanism includes an anvil havinga top and a bottom surface, the bottom surface cooperatively engagingthe probe for its advance into a surface. In this embodiment, the hammermechanism also includes a cylinder attached t6 the anvil that defines achannel for slidable receipt and support of the probe. An end cap ismounted to the cylinder which provides a movable limit for the probe.

In another preferred embodiment, the damping assembly includes a secondenergy absorbing member cooperating with the first energy absorbingmember. Both energy absorbing members being in operative engagement withthe hammer mechanism to attenuate impact forces generated duringoperation of the apparatus. Further, the second energy absorbing membergenerates a recoil force to increase the impact forces. Preferably, thefirst energy absorbing member is slidably supported about the cylinderand cooperates with the bottom surface of the anvil and the secondenergy absorbing member is also slidably supported about the cylinderand cooperates with the end cap. Desirably, the second energy absorbingmember generates the recoil force.

In yet another preferred embodiment, the damping assembly includes abumper member fixedly attached adjacent a proximal portion of thehousing.

In another preferred embodiment, the housing includes a handle assembly.Preferably, the handle assembly includes a first handle portion and asecond handle portion, each portion extending from the housing anddefining an open region therebetween.

In a most preferred embodiment, the plunger apparatus includes a housinghaving a proximal portion and a distal portion and the housing furtherdefines a channel. An elongated probe is also included that is slidablymounted within the housing and axially extending from the distal portionof the housing. A hammer mechanism is included that is cooperativelyengageable with a proximal end of the elongated probe. The hammermechanism includes an anvil and a cylinder mounted within the housing.The cylinder defines a channel for supporting the probe therewithin andthe anvil is slidably movable within the housing and into engagementwith the probe. A spring assembly is mounted within the housing andslidable about the cylinder and engageable with the anvil, the springassembly being operatively associated with the hammer mechanism.Preferably, the elongated probe has an increased diameter portion toretain the probe within the housing.

A method is disclosed for detecting gas leaks, including the steps ofpositioning a plunger adjacent to a gas line, the plunger including, ahousing, a probe, a hammer, and a damping assembly, raising the housingof the plunger to a desired height over a surface, and lowering thehousing to accelerate the hammer to impact the probe towards and intothe surface for detecting a gas leak.

BRIEF DESCRIPTION OF DRAWINGS

The present device will be described in detail in the followingdescription of preferred embodiments with reference to the followingfigures wherein:

FIG. 1 is a side view in cross-section of a plunger bar in accordancewith the prior art;

FIG. 2 is a perspective view of an embodiment of the plunger bar held bya hand of an operator above an intended penetration site;

FIG. 3 is a side view in partial cross-section of an embodiment of aplunger bar;

FIG. 4 is an exploded perspective view of an embodiment of a plungerbar;

FIG. 5 is a cross-sectional view, in-part elevation, of an alternateembodiment of the present disclosure;

FIG. 6 is another embodiment of the plunger bar held by an operator; and

FIG. 7 is yet another embodiment of the plunger bar held by an operator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The preferred embodiment(s) of the method and apparatus disclosed hereinare discussed in terms of penetrating procedure and devices for makingholes in soil, concentrate and the like. It is further envisioned thatsuch apparatus may be used for detecting sub-surface objects, forexample, in the detection of gas leaks by utility personnel.

In accordance with the present disclosure, referring now in detail tothe drawings wherein like reference numerals identify similar or likecomponents throughout the several views, FIG. 2 describes a plunger bar100 which reduces the impact shock to an operator. Plunger bar 100reduces the impact forces through the use of a spring damper system,described hereinbelow. The shock waves caused by the impact of drivingplunger bar 100 into the ground are thereby attenuated creating acondition of reduced stress to the operator's arms and wrists.

The preferred embodiment of the plunger bar is capable of attenuatingpeak shock waves due to impact, for example from approximately 1500 g'sto about 500 gas. Further, given the damping arrangement, the initialforce imparted to plunger bar 100 is reduced from the prior art, forexample 36% less force need be supplied by the operator to cause thesame effect.

As shown in FIG. 2, plunger bar 100 is held above an intendedpenetration site 102 by a hand 104 of an operator. Plunger bar 100 isillustrated with a two-piece barrel 105 having a proximal portion 106and a distal portion 108. As used herein, the term "proximal" refers tothat portion or end which is furthest from the intended penetrationsite, and the term "distal" refers to that portion or end which isclosest to the intended penetration site. Since plunger bar 100 ismanually operated, barrel 105 is preferably sized to accommodate thehuman hand. The preferred shape of barrel 105 is cylindrical. It isenvisioned that the weight of barrel 105 may be varied according to anintended application. An optimal weight will create holes as well asallow the efficient use of plunger bar 100 by the operator. Probe 110 isillustrated extending from the distal end of barrel 105 toward theintended penetration site 102. Thus, the operator's hand 104 is moveddistally, as indicated by arrow C, to move barrel 105 distally andthereby force probe 110 to penetrate the intended penetration site 102.

As illustrated in the cross-sectional view of FIG. 3, one preferredembodiment of the spring damper arrangement of the present disclosureincludes a gap D provided between a bumper 112 and a proximal end of ahammer mechanism 114. Bumper 112 is preferably constructed of acompressible material, such as neoprene or other resilient, rubbermaterial. When the operator lifts the device in a proximal direction,plunger bar probe 110 slides within hollow cylindrical portion 124 (aswill be described below) so that the proximal end of probe 110 separatesand is spaced from a distal end of hammer mechanism 114 within portion124. As the operator moves a barrel 105 distally, momentum is acquiredprior to hammer 114 striking the proximal end of probe 110. As hammer114 strikes probe 110, probe 110 is driven into penetration site 102.The downward impact force is attenuated by springs 128 and 130, and theblow of hammer 114 is softened by bumper 112 creating the damping effectthat reduces the stress on the operator's arms and wrists. Theindividual components of plunger bar 100 will be described withreference to the exploded perspective view shown in FIG. 4.

Referring now to FIG. 4, plunger bar 100 is illustrated in an explodedperspective view to show the assembly of the individual components. Aproximal end 116 of plunger bar 100 includes an end cap 118 havingbumper 112 attached thereto and is fixedly connected to the proximal endof proximal portion 106 of barrel 105. Proximal portion 106 may bethreadably connected at a distal end thereof via threaded coupling 120to a proximal end of distal portion 108, which may also be threadablycoupled to coupling 120.

Hammer 114 includes a solid anvil portion 122 attached to a hollowcylindrical portion 124, and an end cap 126 threadably fixed at threadedend 125 to a distal end of cylindrical portion 124. A first spring 128is configured and dimensioned to be slidably mounted on hollowcylindrical portion 124 between anvil 122 and coupling 120, and a secondspring 130 is configured and dimensioned to be slidably mounted oncylindrical portion 124 between coupling 120 and an end cap 126. Whilemounted on cylindrical portion 124, spring 128 is restrained from axialmovement on its proximal end by anvil 122 and on its distal end bycoupling 120. Similarly, second spring 130 is restrained from axialmovement on its proximal end by coupling 120 and on its distal end byend cap 126. End cap 126 has a longitudinal bore therethroughdimensioned to insertably receive probe 110. Probe 110 is furtherreceived within a longitudinal bore formed within cylindrical portion124. A flange 132 is formed on the proximal end of probe 110 to preventprobe 110 from completely sliding out of end cap 126.

In use, as an operator prepares to create a hole with plunger bar 100, adistal tip of probe 110 is positioned on a location for the desiredhole. The plunger bar is lifted in the direction of Arrow "A", as seenin FIG. 2, and once the desired height is reached by the operator,barrel 105 is accelerated downward in the direction of Arrow "C" causinganvil 122 of hammer 114 to impact flange 132 of probe 110. Upon impact,probe 110 is driven into the ground. The downward stroke is attenuatedby springs 128 and 130. The motion of hammer 114, that is propelled inpart by the recoil force of springs 128 and 130, is dampened by bumper112, which impacts an upper surface 123 of hammer 114. Because theoperator holds only barrel 105, the impact shock waves are attenuatedthrough springs 128 and 130 and bumper 112 during the entire impactprocedure. Hence, the stress on the arms and wrists of the operator isreduced. Thus, in accordance with the above description of the presentlydisclosed plunger bar, the impact force which is typically imparted uponthe operator is effectively attenuated by both bumper 112 and springs128 and 130.

It is envisioned that springs 128 and 130 are configured, as shown inthe preferred embodiments, with respect to hammer 114 to advantageouslyprovide a system for enhancing the force which is exerted upon plunger100. That is, the downward motion of bumper 112 and hammer 114 causespring 130 to compress between coupling 120 and end cap 126. Sincecoupling 120 is, at least momentarily, held in a fixed position by thehand of the human operator, at least a portion of the recoil forceexerted by spring 130 will be directed distally against end cap 126. Thespring force exerted on end cap 126 will be transferred throughcylindrical portion 124 to anvil 122 which is in contact with theproximal end of probe 110. Hence, the force exerted by hammer 114 onprobe 110 will be increased. Therefore, the operator will experienceless fatigue and will more effectively drive plunger 100 into theground, while exerting the same force which was required by conventionalplunger bars.

Thus, in accordance with the apparatus as described above, a plunger baris provided which reduces the fatigue and stress to the operator whichresults from the impact forces associated therewith, and also increasesthe penetration force of probe 110.

In another embodiment, barrel 105 includes a handle assembly 200,facilitating manual operation of plunger 100. As shown in FIG. 5, handle200 includes a first handle portion 204 and a second handle portion 206.In the embodiment shown, both handle portions 204 and 206 extend frombarrel 105 defining open regions 210 and 212, respectively. Open region210 and 212 provide sufficient area for an operator to grip handleportions 204 and 206 with his or her hand(s).

In use, as shown in FIG. 6, an operator may grip an individual handleportion, 204 or 206, for operating and manipulating plunger 100 asdescribed hereinabove. Here, operator hand 104 grips handle portion 204.Alternatively, as shown in FIG. 7, an operator may grip handle portion204 and 206 simultaneously with both hands to exert a greater amount offorce and stability while operating plunger 100.

Having described the above embodiments of an improved plunger bar (whichare intended to be illustrative and not limiting), it is noted thatmodifications and variations could be made by those skilled in the artin light of the above teachings. It is therefore to be understood thatchanges may be made in the particular embodiments which are within thescope and spirit of the disclosure.

What is claimed is:
 1. A plunger apparatus for penetrating a surface,the apparatus comprising:a housing; a probe configured to penetrate thesurface and slidably supported by the housing; a hammer mechanismslidably supported by the housing and cooperatively engaging the probeto distally advance the probe into the surface; and a damping assemblysupported by the housing, the damping assembly including at least oneenergy absorbing member cooperating with the hammer mechanism toattenuate impact forces generated during the operation of the apparatus.2. The plunger apparatus according to claim 1, wherein the hammermechanism includes:an anvil having a top and a bottom surface, thebottom surface cooperatively engaging the probe to distally advance theprobe, a cylinder having a proximal and a distal end, the cylinderfixedly attached to the bottom surface of the anvil at its proximal endand defining a channel therewithin for slidable receipt and support ofthe probe, and an end cap mounted at the distal end of the cylinder, theend cap defining a distal movable limit for the probe.
 3. The plungerapparatus according to claim 1, wherein the damping assembly ispositioned within the housing to generate a recoil force for cooperatingwith the hammer mechanism to increase impact forces for driving theprobe into a surface.
 4. The plunger apparatus according to claim 3,wherein the damping assembly further includes a second energy absorbingmember cooperating with the first energy absorbing member, both membersbeing in operative engagement with the hammer mechanism to attenuateimpact forces generated during operation of the apparatus, the secondenergy absorbing member generating the recoil force to increase impactforces.
 5. The plunger apparatus according to claim 2, wherein theenergy absorbing member of the damping assembly includes a first energyabsorbing member slidably supported about the cylinder and cooperatingwith the bottom surface of the anvil, a second energy absorbing memberslidably supported about the cylinder and cooperating with the end cap.6. The plunger apparatus according to claim 5, wherein the dampingassembly is positioned within the housing whereby the second energyabsorbing member generates a recoil force transmitted to the end cap,the recoil force firther transmitted to the cylinder and to the anvilthereby increasing the impact forces for driving the probe into asurface.
 7. The plunger apparatus according to claim 1, wherein thedamping assembly further includes a bumper member fixedly attached to aproximal portion of the housing, the bumper member cooperating with thehammer mechanism to attenuate impact forces generated during operationof the apparatus.
 8. The plunger apparatus according to claim 1, whereinthe at least one energy absorbing member comprises a spring assembly. 9.The plunger apparatus according to claim 6, wherein the first and secondenergy absorbing members are springs.
 10. The plunger apparatusaccording to claim 1, wherein the probe has an increased diameterportion adjacent a proximal end thereof for retaining at least a portionof the proximal end of the probe within the housing.
 11. The plungerapparatus according to claim 1, wherein the housing includes a handleassembly.
 12. The plunger apparatus according to claim 11, wherein thehandle assembly comprises a first handle portion and a second handleportion, each portion extending from the housing and defining an openregion therebetween.
 13. A plunger apparatus, comprising:a housinghaving a proximal portion and a distal portion and defining a channeltherewithin; an elongated probe configured to penetrate a surface andslidably mounted within the housing and axially extending from thedistal portion of the housing; a hammer mechanism cooperativelyengageable with a proximal end of the elongated probe, the hammermechanism including an anvil and a cylinder mounted within the housing,the cylinder fixedly attached to the anvil and defining a channel forsupporting the elongated probe therewithin, the anvil being slidablymovable within the housing and into engagement with the elongated robefor driving the elongated probe into the surface; and a spring assemblymounted within the housing and slidable about the cylinder andengageable with the anvil, the spring assembly operatively associatedwith the hammer mechanism to attenuate impact forces generated duringoperation of the apparatus to a user.
 14. The plunger apparatusaccording to claim 13, wherein the spring assembly is positioned withinthe housing to increase a driving force for driving the probe into asurface, whereby a first spring generates a recoil force due toengagement with the hammer mechanism, the recoil force generatedincreasing the impact forces generated, and the first spring and asecond spring cooperating with the hammer mechanism to attenuate impactforces generated during operation of the apparatus.
 15. The plungerapparatus according to claim 13, wherein the elongated probe has anincreased diameter portion adjacent a proximal end thereof for retainingat least a portion of the proximal end of the probe within the housing.16. A method for detecting gas leaks, comprising the stepsof:positioning a plunger apparatus adjacent to a gas line, the plungerapparatus including: a housing, a probe, a hammer and a dampingassembly; raising the housing of the plunger apparatus to a desiredheight over a surface adjacent to the gas line; and lowering the housingto accelerate the hammer to impact the probe of the plunger apparatustowards and into the surface for detecting a gas leak.
 17. The methodaccording to claim 16, wherein the steps of raising and lowering areconsecutively performed for multiple iterations sufficient to detect agas line below the surface.